Becker's vacuum gauge operated in the decremental mode

Abstract

Various friction vacuum gauges were developed in the past. When electronically driven they were usually operated in continuous mode, because the electronics is easier. Present electronics enables operation in the decremental mode as well, thus extending the measuring range. This paper reports operation of Becker's vibrating ribbon gauge in the decremental mode. The vibration of the ribbon was excited by a series of current pulses derived from the natural frequency of the ribbon. When the desired amplitude of the ribbon was reached the excitation pulses were stopped and the damped harmonic signal was recorded. The computed time constant is the measure of the pressure. The gauge was calibrated over the range 10−5–103mbar. These measurements confirmed that in the decremental mode the lower pressure limit is decreased as compared to the original continuous mode.